Most of the protesters in Union Square called for amnesty for undocumented immigrants, but the multiple chants from the stage were inaudible.

Some groups waved flags, others held up banners decrying "capitalism's evils," and a few did a Mexican dance in colorful garb. Some protesters donned the Guy Fawkes mask that has come to represent Occupy Wall Street.

Victor Castellano, a trustee with the Teamsters Local 553, said the traditional May Day message was "heavily diluted" at the rally. "You have a whole bunch of people now with different agendas," said Castellano, 58, of Whitestone. "We're not looking for an end to Wall Street or beginning of socialism, we just want fair labor laws."

When the noise died down at the park, the demonstrators hit the streets in a tightly controlled march down Broadway to Foley Square near City Hall. Police and protesters were calm for most of the hike downtown, with marchers stopping occasionally to chant.

Some of the day's protests, however, weren't as calm. More than 100 protesters gathered in the East Village earlier in the afternoon and butted heads with officers there. A small scuffle ensued, and at least six people were arrested, according to a witness. At press time, the NYPD couldn't say how many protesters were taken into custody.